BA 373 then BA 600 at Heathrow
Toulouse → London → Venezia
Timetable, London time
18:00BA 373 from Toulouse at the gate
17:00BA 600 to Venezia leaves the gate
23 h apart on the timetable, overnight
BA 600 leaves 23 h after BA 373 arrives on the timetable: more than half a day, so not a connection we count.